1. Field of the Invention
The present invention relates to a reworking device, and more particularly to a reworking device for automatically lifting an electrical element mounted on a motherboard without damaging the element as well as the motherboard.
2. Description of Related Art
Surface mounted electronic elements have become a trend in computer industry, especially when the operating speed becomes higher and higher. For example, a chip socket for electrically connecting a central processing unit (CPU) to a motherboard has been evolved from pin grid array (PGA) to ball grid array (BGA) so as to benefit high speed processing.
However, one of the problems associated with the BGA socket and other surface mounted elements is how to remove the mounted BGA socket or the like from a motherboard when it is found defective.
As a matter of fact, a typical BGA socket generally includes more than four hundred solders attached to terminal portions of terminals mounted in the socket. Those solders are arranged in array covering the entire bottom surface of the socket. For the PGA socket, the rework, i.e., removing a mounted PGA socket, can be done by reflowing the solders located between the pin legs of the socket and the through holes in the motherboard and access them from the bottom of the motherboard, while for the BGA socket, it is unlikely to access the solders located under the socket and apply heat to the solders to reflow them thereby separating the BGA socket from the motherboard.
Once the mounted BGA socket or the like is found detective, it has to be trashed away. For a reference, the estimated cost for a motherboard is at least US $50 and even more for high-end motherboard. Trashing it away only because of a defective element inevitably increases the overall cost of the motherboard.
In addition, if the mounted BGA socket is founded defective after assembling to a computer, more problems will e created.
In order to remove the mounted BGA socket or the like from the motherboard, the first problem to be solved is how to apply enough heat to the bottom of the socket to reflow the solders. The second problem is even if the solders are reflown, how to separate them just in time. Another problem is how to evenly and simultaneously heat each solder.
On the other hand, in order to prevent a defective BGA socket from occurring after it is mounted, strict requirements for the accuracy and durability of the BGA socket are required which inevitably increases the overall cost. For example, the coplanarity of the solders has to be controlled at a high precision, for example, 0.0012xe2x80x3 as suggested in U.S. Pat. No. 6,164,983.
Accordingly, an object of the present invention is to provide a reworking device for readily heating solders located between a mounted BGA socket and a motherboard.
A second object of the present invention is to provide a reworking device which can lift a BGA socket such that the BGA socket is completely detached from a motherboard once the solders are reflown.
A third object of the present invention is to provide a reworking device which provides sufficient heat to each and every solder evenly so as to reflow the solders simultaneously.
A fourth object of the present invention is to provide a reworking device which lifts up the mounted BGA socket unintrusively thereby without damaging the motherboard.
A fifth object of the present invention is to provide a reworking device which can largely and automatically lifts up the BGA socket mounted on a motherboard.
In order to achieve the object set forth, a reworking device for removing a surface soldered element from a motherboard comprises a body portion having an elongate strip. A hook is formed at each of two opposite ends of the strip for engaging with a bottom surface of the element. An elastic arm is formed at the each of two opposite ends of the strip adapted to be supported so as to lift up the element when a solder is reflown. The device further comprises an operation arm at the each of two opposite ends. In use, operating the operation arms, the hooks are engaged to the element and the elastic arms supporting at the motherboard. When the element needs to be released from the motherboard, only need to operate the operation arms thereby causing the hooks disengaging with the element so that the element is automatically detached form the motherboard due to the lifting force provided by the elastic arms.